1. Field of the Invention
This invention generally relates to the field of electronic messaging and more specifically to the identification of spoofed electronic messages.
2. Description of Related Art
Internet electronic mail (email) was created in an environment where there were relatively few users of the system, most of whom were known to one another (either directly or through a very short chain of acquaintances), and where it was reasonable to be able to trust information supplied by other users (for example, the user's name and email address). With the growth of the Internet, however, those assumptions have proven not to be tenable, and there is now a large industry of spammers—people who send unsolicited email to millions of recipients in the hopes of getting them to read the email and respond to it. At present, the millions of people who use email are being overwhelmed by billions of unwanted email messages. Surveys show spam now accounts for about half of all email and frequently includes messages that are fraudulent or pornographic. Email is also used to spread viruses and worms. In order for the virus to spread, the email must be opened by the recipient (rather than being discarded unread).
In both of these cases, one of the tricks that the sender uses to cause the recipient to open the email is “spoofing”—pretending to send email from an address other than the sender's own, one which the recipient may be more likely to trust (for example, another user in the same company).
Therefore a need exists to overcome the problems discussed above, and particularly for a way to more efficiently identify spoofed email.